1. Field of the Invention
The present invention belongs to the technological field of an image forming apparatus and particularly relates to the art of recording a bar code in a recording medium.
2. Description of the Related Art
In recent years, printing a bar code in an image forming apparatus such as a printer has become increasingly popular and an even finer bar has come into general use, thereby requiring an improvement in printing precision for a bar code. In order to print a bar code more precisely, for example, Japanese Patent No. 3370711 disclosed an art of forming a bar code with a black bold line, a black fine line, a white bold line and a white fine line, and in consideration of the fact that an ink runs, printing each line (bar) of the bar code which is finer than a width necessary for each line of an ordinary bar code and determining the number of dots forming each line in such a way that the line width becomes optimum after an ink runs.
In short, the art disclosed in Japanese Patent No. 3370711 is designed to print the black bold line, black fine line, white bold line and white fine line having appropriate widths, merely by paying attention to the thickness of each bar.
However, there are a number of parameters determining printing precision for a bar code: a bar thickness, as well as a bar density, whether a white line is accurately white, whether a bar is partly omitted, and the like. In Japanese Patent No. 3370711, these parameters other than the bar thickness are not taken into account, thereby leaving room for printing a bar code more precisely.
In addition, if a general-purpose image forming apparatus which prints various objects including a bar code executes an image processing for fining a line to thereby upgrade the image of a bar code, the quality of an ordinary image except the bar code may be deteriorated.